Failure of nocturnal prolactin suppression by methysergide to entrain changes in testosterone in normal men

Hyperprolactinemic infertile men

Clinical descriptions of prolactin in states of oversecretion are presented in 49 patients that presented for infertility investigation. Radiological assessment did not reveal microadenomas in these patients. Erectile dysfunction or deficient semen parameters could be early manifestations of hyperprolactinemia in some infertile men.

Effects of sulpiride induced hyperprolactinemia on testosterone secretion and metabolism before and after HCG in normal men

The purpose of the study was to investigate the effects of sulpiride-induced hyperprolactinemia on testicular functions, as assessed by evaluation of plasma testosterone (T), dihydrotestosterone (DHT) and 17 beta-estradiol (E2) levels. An HCG test (5000 IU on three consecutive days) was performed in basal conditions and after 12 and 26 days of sulpiride treatment (150 mg daily) in 7 male volunteers, 19 to 32 years of age, as well as in 6 sulpiride-free controls. The results show that after 12 days of induced hyperprolactinemia (mean increase 400%) the T response to HCG was similar to basal test; after 26 days however, the increase of T mean plasma levels was significantly greater. The increase in E2 significantly correlated to that of T during the first and second HCG tests, but no longer after 26 days of hyperprolactinemia, resulting in an imbalance of the E2/T ratio of plasma increments. The response of DHT to HCG was significant in basal conditions and after 26 days of sulpiride and always correlated with T behavior. Data obtained in our experimental conditions suggest that PRL might enhance T secretion. 5 alpha-reductase activity seemed to be partially affected after 12 days of treatment, while a significant inhibition seemed to be exerted on aromatase activity.

Nyctohemeral pattern of serum LH, FSH and PRL in patients with myotonic dystrophy

The nyctohemeral pattern of serum luteinizing (LH), follicle-stimulating hormone (FSH) and prolactin (PRL) in eight patients with myotonic dystrophy (MD) was studied. Gonadotropin patterns were classified as adult, pubertal or infantile. Six patients showed an adult pattern, whereas two had a pubertal or infantile pattern. A normal pattern of PRL secretion was found in seven patients and a blunted sleep-related hormonal increase was observed in one. Impaired hypothalamic control of pituitary secretion in MD is proposed as the cause for these findings.

Relationship of changes in serum concentrations of prolactin and testosterone during dopaminergic modulation in males

To evaluate the effect of PRL on the male pituitary-gonadal system, serum concentrations of PRL, testosterone, LH and FSH were determined in healthy young men daily before, during, and after 3-day oral administration of bromocriptine, metoclopramide or sulpiride. Bromocriptine (2.5 mg as a single dose) caused, concurrently with a marked suppression of serum PRL, a significant increase of serum testosterone and a transient decrease of serum LH. The changes of PRL and testosterone were negatively correlated. With metoclopramide (10 mg q.i.d.) serum PRL was increased and testosterone inversely decreased. There was no change in LH and FSH. Sulpiride (50 mg q.i.d.) evoked the elevation of serum PRL and LH, but no change in testosterone. A significant increase in serum concentration of testosterone was also observed in a patient with PRL-producing pituitary tumour and four out of seven patients with acromegaly during bromocriptine treatment. These results suggest an inhibitory effect of PRL on testosterone secretion at the gonadal level, or direct dopaminergic stimulatory control of testosterone secretion.

Bromocriptine therapy in oligozoospermic infertile men

A prospective, randomized double-blind study with crossover using bromocriptine and placebo was performed on a group of 17 infertile males with idiopathic oligozoospermia. Twelve patients completed the duration of this study of eight months by receiving 5 mg of bromocriptine per day for four months followed by four months of placebo or vice versa. Prior to treatment, the sperm count was 8.76 +/- 1.32 (10(6)/ml). The hormonal profile was performed prior to treatment and included estimation of prolactin, T3, T4, thyroid stimulating hormone (TSH), testosterone, follicle stimulating hormone (FSH), and plasma LH. Stimulation studies using LHRH and TRH were also performed. All hormonal estimations were within normal limits. Compared to placebo, bromocriptine had no significant effect on sperm analysis, or basic hormonal profile. The stimulation test with luteinizing hormone releasing hormone (LHRH) was unchanged except for the basic plasma testosterone, which increased. The prolactin decreased following the thyrotropin releasing hormone (TRH) stimulation. Two pregnancies were noted four to six weeks following the end of treatment. Bromocriptine did not seem to be more effective than placebo in the treatment of idiopathic oligozoospermia.

Pituitary function in normoprolactinaemic infertile men receiving bromocriptine

A double blind trial of bromocriptine 7.5 mg daily versus placebo was carried out in ten infertile men. Pretreatment basal plasma prolactin, thyroid stimulating hormone (TSH) testosterone and luteinizing hormone (LH) concentrations were normal, but plasma follicle-stimulating-hormone (FSH) was raised in four individuals. After 4 months treatment with bromocriptine a significant fall in plasma prolactin was observed (P less than 0.01), both under basal conditions and following thyroid stimulating hormone releasing hormone (TRH). Basal plasma gonadotrophin, testosterone and thyroid stimulating hormone (TSH) concentrations did not alter. No change in sperm density, volume or motility was noted. However an apparent fall in the peak plasma LH (but not FSH) response to gonadotrophin releasing hormone (LHRH) was observed in patients receiving bromocriptine. This reduction in plasma LH responsiveness was significant when compared with the baseline response (P less than 0.05) but failed to reach significance when compared with the placebo response. It is concluded that prolonged bromocriptine therapy in normoprolactinaemic men does not suppress FSH secretion, and any reduction in plasma LH responsiveness to LHRH is not accompanied by a significant fall in plasma testosterone.